This invention relates to an improved process for winding filaments about a mandrel. More particularly, this invention relates to a filament winding apparatus having means associated with the winding process using ring thereof for automatically clearing away residue and debris which accumulates therein during operation and causes filament breakage.
Apparatus for simultaneously winding a plurality of filaments about a mandrel in a helical manner are well known in the art and have been discussed, for example, in U.S. Pat. Nos. 3,201,298 and 3,032,461. Such apparatus generally consists of a mandrel and a winding ring peripherally surrounding the mandrel which serves to guide a plurality of filaments to the surface of the mandrel in a radial fashion. The winding ring and mandrel are capable of undergoing reciprocating axial movement and rotating with respect to each other, so that when a plurality of filaments in peripherally distributed arrangement are passed through the winding ring onto the surface of the mandrel, they are helically wound about the mandrel in a continuous manner by this reciprocating and rotating motion. If desired, a plurality of winding rings may be spaced about the mandrel to allow more than one layer of filaments to be applied to the mandrel at a time. These winding rings may be constructed in a number of ways, but conveniently are comprised of two adjacently situated annular plates which lie concentric to the mandrel and which have oppositely facing surfaces between which the filaments pass and by means of which they are guided to the mandrel.
Filament winding apparatus of this type has been successfully used to continuously wind glass and other filaments without the occurrence of any problems. However, when attempts were made to wind carbon fibers with this equipment, it was found that a considerable amount of debris in the form of a fine fluff would accumulate in and block the winding ring due to the susceptibility of the fiber to shed or fragment. When the winding ring also served as a means for dispensing and applying a resin binder to the fibers, the problem was accentuated by the accumulation of resin in the ring. As a result of this accumulation of residue, and the high fragility and brittleness of carbon fibers, frequent filament breakage would occur which necessitated shutting down the equipment and interrupting production in order to allow the winding ring to be cleaned.